1. Field
Embodiments relate to a back light unit and a manufacturing method thereof, and, more particularly, to a back light unit and a manufacturing method thereof capable of reducing the number of constituent components and improving efficiency of a manufacturing process.
2. Description of the Related Art
Recently, as a personal computer, television or the like becomes light and thin, a display device is also required to be light and thin. According to such a demand, a flat panel display such as a liquid crystal display (LCD) device has been developed instead of a cathode ray tube (CRT).
The liquid crystal display device is a display device in which an electric field is applied to a liquid crystal material having an anisotropic dielectric constant, which is injected between two substrates. The intensity of the electric field is adjusted to adjust the amount of light which is transmitted from an external light source (back light) to the substrate to thereby obtain desired image signals.
The liquid crystal display device is a typical one among portable flat panel display devices. Among them, TFT-LCD using a thin film transistor (TFT) as a switching device is mainly used.
The liquid crystal display device includes a liquid crystal display panel to display images; a gate driver driving unit to supply a scanning signal to the liquid crystal display panel; a source driver to supply a data signal to a pixel selected for the scanning signal; a back light unit to irradiate red (R), green (G) and blue (B) light to the liquid crystal display panel; a back light controller to control the back light unit; and a timing controller to supply control signals for controlling the liquid crystal display panel, the gate driver, the source driver and the back light controller.
In relation to the back light unit, the liquid crystal display device is a display device to display various types of information, but it is a non-luminous body incapable of emitting light. Accordingly, it is necessary for an additional device to lighten the liquid crystal display panel by placing a light source on a rear surface of the liquid crystal display panel. The back light unit performs such a function.
However, in the conventional back light unit, a reflecting plate, a mold frame and a bezel are separated from each other. Accordingly, since the steps and the assembling process are complicated, it takes a lot of cost and the back light unit has a large thickness. Further, since the mold frame is made of a plastic material, the loss of light generated at an edge portion of the back light unit brings a reduction of brightness.
In order to solve such problems, Korean Patent Laid-open Publication No. 10-2006-93956 discloses a back light unit of a liquid crystal display device including a light guiding plate which is disposed on a rear surface of a liquid crystal display panel to uniformly transmit a light beam; a lamp which generates the light beam at a periphery of the light guiding plate; a diffusion sheet which diffuses the light beam passing through the light guiding plate; a prism sheet which controls a traveling direction of the light beam passing through the diffusion sheet; and an integrated reflective member which reflects the light beam to the light guiding plate and supports the light guiding plate, the lamp, the diffusion sheet and the prism sheet.
In the back light unit disclosed in the Publication, the integrated reflective member functioning as the bezel, the reflecting plate and the mold frame is manufactured of metal having an excellent reflectivity, thereby simplifying the assembling process and reducing the cost.
However, an additional reflecting plate should be provided in the integrated reflective member and be coupled to the bezel, and an operation for coupling the light guiding plate should be performed. Accordingly, there are problems such that the assembling process is still complicated, and it is difficult to unify the light guiding plate and the integrated reflective member due to different materials thereof.